A door that was closed is now open.
In a Los Angeles operating room on May 4, surgeons from UCLA and USC crossed a threshold that medicine had never before reached — successfully transplanting a human bladder for the first time in history. The patient, Oscar Larrainzar, a 41-year-old father of four, had spent seven years bound to a dialysis machine after cancer and surgery stripped him of his kidneys and bladder. What two surgeons spent four years quietly building in research and technique became, in eight hours of surgery, a new chapter in what the human body can be given back. A door that did not exist has now been opened.
- A 41-year-old father of four spent seven years on dialysis with no transplant option available — until now.
- The surgery required not just transplanting an untested organ, but connecting a donor kidney to a donor bladder using a technique that had never been performed on a living human.
- Within hours of the procedure, the new kidney began producing urine in large volumes and Larrainzar no longer required dialysis — the connections held.
- Three days post-surgery, the patient was reported to be doing well, with his clinical progress satisfying the surgical team.
- With over 82,000 Americans diagnosed with bladder cancer annually, this breakthrough opens a transplant pathway that previously did not exist for patients facing permanent organ loss.
On May 4, at Ronald Reagan UCLA Medical Center, a surgical team did something that had never been done before: they transplanted a human bladder. The patient was Oscar Larrainzar, a 41-year-old father of four whose cancer had taken both his kidneys and whose tumor removal had destroyed his bladder. For seven years, he had lived tethered to a dialysis machine, with no viable path forward — until now.
The surgery was the result of four years of collaboration between Dr. Nima Nassiri of UCLA and Dr. Inderbir Gill of USC's Institute of Urology. Together, they designed a clinical trial and developed the surgical technique that made the procedure possible. On the day of the operation, the team first recovered a donor kidney and bladder, then performed the intricate work of connecting them — a process that had to succeed completely or not at all.
It succeeded. Within hours, the new kidney was producing urine in large volumes. Larrainzar needed no dialysis after the operation. By the third day, his surgical team reported he was progressing well. When asked what he hoped for, Larrainzar said simply: 'My hope is to have a better life.'
The implications reach far beyond one man's recovery. Bladder cancer affects more than 82,000 Americans each year, and many survivors face permanent organ dysfunction with no transplant option available to them. Nassiri and Gill are already planning future procedures, and the technique they developed is now replicable. The question is no longer whether a bladder transplant can be done — it is how many will follow.
On May 4, in an operating room at Ronald Reagan UCLA Medical Center in Los Angeles, a surgical team completed a procedure that had never been attempted on a living human before. They transplanted a bladder—an organ that had never successfully been moved from one person to another. The patient was Oscar Larrainzar, a 41-year-old father of four who had lost most of his bladder years earlier during surgery to remove a tumor. For seven years, he had depended on dialysis to keep him alive. Now, after eight hours in surgery, he had a new bladder and a new kidney, both from a donor, both connected using a technique that two surgeons had spent four years developing.
Larrainzar's medical history reads like a cascade of complications. Cancer had taken both his kidneys. The tumor removal had destroyed his bladder. He had been tethered to a dialysis machine for seven years—a grinding, repetitive necessity that defines the lives of people whose organs have failed. For someone in his position, the options were limited and grim. A bladder transplant was not one of them. It had never been done. Until now.
Dr. Nima Nassiri, an assistant professor of urology at UCLA who specializes in kidney transplantation, and Dr. Inderbir Gill, the founding executive director of USC's Institute of Urology, had been working toward this moment since 2021. They designed a clinical trial. They pioneered a surgical technique. They waited for the right patient, the right donor, the right alignment of circumstances. Gill's department at USC had already established itself as a leader in advanced robotic surgery for urologic cancers. Nassiri's program at UCLA focused specifically on vascularized composite bladder transplants—a category that, until May 4, existed only in theory.
The surgery itself was intricate. The team first recovered the donor kidney, then the donor bladder, at a OneLegacy facility in Azusa, California. Then came the delicate work of connection: attaching the new kidney to the new bladder using the technique Nassiri and Gill had developed. Everything had to work. The kidney had to produce urine. The bladder had to hold it. The connections had to hold.
They did. Within hours of surgery, the new kidney began producing urine in large volumes. Larrainzar's kidney function improved immediately. He did not need dialysis after the operation. Urine drained properly into the new bladder. By Sunday, three days after the procedure, Gill reported that Larrainzar was doing well and that his clinical progress satisfied the surgical team. When asked what he hoped for, Larrainzar was direct: "My hope is to have a better life."
The significance of this surgery extends beyond one patient's recovery. Bladder cancer alone is expected to affect more than 82,000 Americans in a given year, with roughly 16,700 deaths. Many patients who survive bladder cancer face permanent organ dysfunction. Some require complete bladder removal. Until now, there was no transplant option for them. Nassiri's comment—"For the appropriately selected patient, it is exciting to be able to offer a new potential option"—understates what has just become possible. A door that was closed is now open.
The surgeons are already thinking ahead. Nassiri and Gill hope to perform more bladder transplants in the near future. The four-year collaboration between UCLA and USC has produced not just a successful surgery but a replicable technique. Other surgical teams can learn from what happened in that operating room. Other patients, facing the same bleak choices Larrainzar faced, may soon have a choice they did not have before. The first bladder transplant is complete. The question now is not whether it can be done, but how many times it will be.
Notable Quotes
This first attempt at bladder transplantation has been over four years in the making.— Dr. Nima Nassiri, UCLA
My hope is to have a better life.— Oscar Larrainzar, transplant recipient
The Hearth Conversation Another angle on the story
Why does a bladder transplant matter more than, say, perfecting dialysis machines? People have survived on dialysis for decades.
Dialysis keeps you alive, but it doesn't give you your life back. Seven years on a machine means seven years of appointments, restrictions, the constant awareness that your body isn't working. A transplant, if it holds, means freedom.
But this is one patient. One surgery. How do we know it will work for others?
We don't yet. That's why they designed a clinical trial. But the fact that it worked at all—that the kidney produced urine immediately, that the connections held—that's the proof of concept. Now they can refine it, teach it, repeat it.
What made Larrainzar the right patient for this?
He had nothing to lose and everything to gain. He'd already lost both kidneys to cancer. His bladder was gone. He was seven years into dialysis. He was willing to take the risk on something that had never been done before.
The surgeons spent four years on this. What were they doing all that time?
Designing the technique, testing it in models, getting regulatory approval, waiting for the right donor and the right patient to align. Surgery is the last step. Everything before it is preparation.
What happens now if the transplant fails?
That's the unknown. They're watching him closely. But even if it fails, they've learned something. They've proven it's possible. That changes everything for the next patient.
Do you think Larrainzar understands what he's part of?
He said he hopes for a better life. That's what he's focused on. But yes, he's part of something larger—the moment when an impossible thing became possible.